All modern combines include at least a pair of substantially horizontal perforated sieve plates. The harvested grain is deposited on the upper sieve plate, and a fan directs air upwardly and rearwardly through this plate to blow away the chaff and foreign material and to permit the clean grain to fall through the perforations of the plate. Normally, a second sieve plate is located below and in spaced relation to the first sieve plate where the same action is repeated.
The problem created by the sieve plates of the modern combines is that depending upon the speed of the combine and the harvesting conditions, some harvested grain accumulates on the rearward end of the upper sieve plate and falls out of the combine and onto the ground because of the high velocity draft of the combine fan. This condition can be reduced by slowing the speed of the combine, but this obviously reduces the efficiency of the harvesting operation. For example, conventional combines harvesting wheat can lose up to two bushels per acre off of the rearward end of the upper sieve plate while harvesting at a speed of around four miles per hour. This loss of grain can be reduced, but not eliminated, by slowing the speed of the combine down to around three miles per hour.
It is therefore a principal object of this invention to provide a sieve plate baffle attachment for grain combines which will substantially eliminate the loss of harvested grain from the rearward end of the upper sieve plate.
It is a further object of this invention to provide a sieve plate baffle attachment for grain combines which will permit the combine to function at maximum ground speed without losing grain from the rearward end of the upper sieve plate.
A further object of this invention is to provide a sieve plate baffle attachment for grain combines which is readily adaptable to combines of all designs.
A still further object of this invention is to provide a sieve plate baffle attachment for grain combines which is easily manufactured, durable in use, and easily operated.
These and other objects will be apparent to those skilled in the art.